<template>
    <div class="todo-footer" v-show="total">
        <label>
        <!-- <input type="checkbox" :checked="isAll" @change="checkAll" /> -->
        <input type="checkbox" v-model="isAll" />
        </label>
        <span>
        <span>已完成{{doneTotal}}</span> / 全部{{total}}
        </span>
        <button class="btn btn-danger" @click="clearAll">清除已完成任务</button>
    </div>
</template>

<script>
    export default {
        name:'MyFooter',
        //props:['todos','checkAllDone','clearAllTodo'],
        props:['todos'],
        computed: {
          total(){
            return this.todos.length
          },
          doneTotal(){
            // reduce 统计
            return this.todos.reduce((pre,current)=>{
              //console.log('@',pre,current)
              return pre + (current.done ? 1 : 0)
            },0)
          },
          // isAll(){
          //   return this.doneTotal === this.total && this.total > 0
          // }
          isAll:{
            get(){
              return this.doneTotal === this.total && this.total > 0
            },
            set(checked){
               // props 方式
              //this.checkAllDone(checked)
              // 自定义事件发生
              this.$emit('checkAllDone', checked);
            }
          }
        },
        methods: {
         /*  checkAll(e){
            this.checkAllDone(e.target.checked)
          } */
          clearAll(){
            // props 方式
            //this.clearAllTodo()
            this.$emit('clearAllTodo');
          }
        },  
    }
</script>

<style scoped>
    /*footer*/
  .todo-footer {
    height: 40px;
    line-height: 40px;
    padding-left: 6px;
    margin-top: 5px;
  }

  .todo-footer label {
    display: inline-block;
    margin-right: 20px;
    cursor: pointer;
  }

  .todo-footer label input {
    position: relative;
    top: -1px;
    vertical-align: middle;
    margin-right: 5px;
  }

  .todo-footer button {
    float: right;
    margin-top: 5px;
  }
</style>